9W2YII: September 2009

Friday, September 25, 2009

Cara mengira simplex channel V16 SEHINGGA V47 Simplex V16 sehingga V47 menggunakan 145MHz sebelum titik perpuluhan (Desimel).Oleh itu kita hanya perlu mencari MHz selepas titik perpuluhan (Desimel).

Formulanya 12.5 DARAB dengan V Channel.

Contoh 1:
V16 12.5 x 16 = 200
Oleh itu Frekuensi V16 ialah 145.2000

Contoh 2:V2712.5 x 27 = 337.5
Oleh itu Frekuensi V27 ialah 145.33752.

V48 SEHINGGA V63Simplex V48 sehingga V63 menggunakan 146MHz sebelum titik perpuluhan (Desimel).

Formulanya 12.5 DARAB dengan V Channel TOLAK 200

Contoh 1:
V50 12.5 x 50 = 625 TOLAK 200 = 425
Oleh itu Frekuensi V50 ialah 146.4250

Contoh 2:
V63 12.5 x 63 = 787.5 TOLAK 200 = 587.5
Oleh itu Frekuensi V63 ialah 146.5875

Nota:Oleh kerana selepas titik perpuluhan (Desimel) ada 4 nombor maka jika 3 nombor, ditambah dengan 0 sahaja untuk mencukupkan 4 nombor.

Saturday, September 19, 2009

colek PUTRA Pasir Puteh

0 comments at 2:15 AM

Majlis Eyeball Colek anjuran Kelab Putra Pasir Puteh

bagi mempertemukan antara rakan ham setempat dan rakan perantauan

pada 18 september 2009

ambo mewakili ARECTMJ menyampaikan ucapan aluan

Paksu Li

9W2RLL

Ustaz Ismail
9W2ISM

Rakan dari Kuala Ganu

Ustaz Haris
9W2HGM (berkupiah)

9W2YUM
pakai topi

9W2DJM (Din Janggut Merah)
pakai Vest Hitam

9W2STH
baju merah putih

sesi bergambar kenangan
antara rakan Ganu, Perak & Kelantan

9W2UCC 9W2DGW 9W2YGC 9W2???

ZUL Ismail Cikgu Yoong ???

Rakan ARECTMJ beramah mesra

9W2HSO 9W2PDT 9W2TRT 9W2KDK

pak Dollah Pak Din Pak Lie Pak Din

9W2WIE

baju biru

9W2NTM 9W2DTM 9W2TMI 9W2CMB

9W2TXT SWLPKO ??? SWLASO

9W2CMM (mat kaset baju itam)

9W2JCD 9W2HKS

9W2KEY

Pok Ki (pakai topi)

9W2BSS (baju kuning)

orang kuat ARECTMJ

Rakan Akrab Bachok

9W2PKG
pak ku Besut

bermesra dengan PNR

9W2BTS 9W2BNG

cikgu Nazri Bung Krai

9W2MEM (tengah)

Micheal Besut

Pemilik Bot pelancong

9W2NZE
N Mohd Zamri

????

9W2DPG
gelaran Datok Lan
sebab ada cucu

Terima kasih kepada semua rakan yang memeriahkan

majlis Eyeball Colek anjuran Kelab Putra Pasir Puteh.

Insyaallah lain tahun jumpa lagi

Wednesday, September 16, 2009

Kita yang pernah susah satu masa dahulu pasti ada pengalaman sebegini … kalau tak ada duit untuk makan di sekolah … kita gi main main je waktu rehat … dan bulan puasa mengajar kita menghayati hidup fakir miskin …. bagaimana keadaan nya tanpa makan minum di waktu siang … itu baru sebahagian dari kesusahan yang di alami oleh fakir miskin dalam menjalani hidup seharian tanpa makan minum …

Firman Allah, maksudnya: -

Kalau kamu zahirkan sedekah-sedekah itu (secara terang), maka yang demikian adalah lebih baik (kerana menjadi contoh yang lebih baik). Dan kalau pula kamu sembunyikan sedekah-sedekah itu serta kamu berikan kepada orang-orang miskin, maka itu adalah lebih baik bagi kamu; dan Allah akan menghapuskan dari kamu sebahagian dari kesalahan-kesalahan kamu. Dan (ingatlah), Allah Maha Mengetahui secara mendalam akan apa yang kamu lakukan.

Surah Al Baqarah 2:271

Rebut lah peluang untuk menjamu orang orang miskin berbuka puasa dan bersahur … moga moga Allah akan hapuskan sebahagian kesalahan kita.

Juga, bantu bantu lah fakir miskin yang kurang berupaya untuk sama sama berbahagia di hari raya nanti …

Baca la KISAH BENAR ini......

Hai anak2. Insaflah. Bersyukurlah dgn apa yg ada.

MAAFKAN CIKGU

Saya sangat mengkagumi kerjaya sebagai guru sekolah. Sebuah kisah yang saya paparkan ini saya ulangi dari kisah benar seorang guru beberapa tahun yang lalu.

Ceritanya:

Saya mengajar di sekolah rendah di tengah2 bandaraya Kuala Lumpur. Saya mengajar sesi petang. Salah seorang murid saya setiap hari datang lambat ke sekolah. Kasut dan bajunya selalu kotor. Setiap kali saya bertanya tentang baju dan kasutnya dia hanya berdiam diri. Saya masih bersabar dengan keadaan pakainnya, tetapi kesabaran saya tercabar dengan sikapnya yang setiap hari datang lambat.

Pada mulanya saya hanya memberi nasihat. Dia hanya menundukkan kepala tanpa berkata2 kecuali anggukkan yang seolah2 dipaksa. Kali kedua saya memberi amaran, dia masih juga mengangguk tetapi masih juga datang lambat keesokannya. Kali ketiga saya terpaksa menjalankan janji saya untuk memukulnya kalau masih lambat. Anehnya dia hanya menyerahkan punggungnya untuk dirotan . Airmata saja yang jatuh tanpa sepatah kata dari mulutnya.

Keesokan harinya dia masih juga lambat, dan saya memukulnya lagi. Namun ia masih tetap datang kesekolah dan masih tetap lambat. Suatu hari saya bercadang untuk mengintipnya ke rumahnya. Setelah mendapatkan alamatnya, saya meneruskan niat saya.

Dia tinggal di sebuah kawasan setinggan tidak berapa jauh dari sekolah. Keadaan rumahnya sangat daif. Saya nampak murid saya itu sedang berdiri di depan rumahnya dalam keadaan gelisah. Seorang wanita yang mungkin ibunya juga kelihatan gelisah. Lebih kurang pukul 1.30 seorang anak lelaki sedang berlari2 sekuat hati menuju ke rumah itu. Sambil berlari dia membuka baju sekolahnya. Sampai di depan rumah baju dan kasutnya diserahkan pula kepada murid saya yang terus bergegas memakainya. Sebelum pakaian sekolah sempurna dipakai, dia sudah berlari ke arah sekolah.

Saya kembali ke sekolah dengan penuh penyesalan. Saya memanggil anak itu sambil menahan airmata yang mula tergenang. “Maafkan cikgu. Tadi cikgu pergi ke rumah kamu dan memerhatikan kamu dari jauh. Siapa yang berlari memberikan kamu baju tadi?” Dia terkejut dan wajahnya berubah. “Itu abang saya. Kami kongsi baju dan kasut sebab tak ada baju lain. Itu saja baju dan kasut yang ada. Maafkan saya, cikgu.” Jawabnya “Kenapa kamu tak beritahu cikgu dan kenapa kamu biarkan saja cikgu pukul kamu?” ” Mak pesan, jangan meminta2 pada orang, jangan ceritakan kemiskinan kita pada orang. Kalau cikgu nak pukul serahkan saja punggung kamu.” Sambil menahan airmata yang mula berguguran saya memeluk anak itu, “Maafkan cikgu, …….”

Kejadian itu cukup menginsafkan saya. Selepas itu saya cuba membantunya setakat yang mampu.

Tuesday, September 15, 2009

6 dB Colinear VHF Antenna

0 comments at 8:14 AM

It is not particularly difficult to make a VHF antenna with omni-directional properties as well as having a 6 dB gain*. A "Slim-Jim" antenna is quite popular but only realizes about 1.7 dB of gain*. I had a problem with my packet radio station and decided that antenna gain was the solution. So now I have a 6 dB gain VHF colinear. I also managed to get another 6 dB or so out of my old tired-out IC260A VHF receiver with a bit of dexterous tuning.
(* - referenced to a simple 1/4-wave whip antenna)

This drawing shows the basic construction. There is nothing new about the technology, mounting a half-wave above another is quite common. Both Marconi and Franklin developed similar techniques, but Marconi was more keen on capacitive coupling between the antenna elements whereas Franklin proposed 1/4-wave stubs in a variety of simple and complex forms (Antenna Engineering Handbook by Jasic). My antenna follows the Franklin approach, but using 4mm hard drawn aluminium rods, supported by bits cut out of a nylon chopping board "liberated" from the kitchen (when the wife is not there - of course). Each element and the stub are all a calculated 1/2-wave in length (1030mm) but the stub is to be about 2" (5cm) longer. The stub is folded to form two parallel bars, 5cm apart joined together at one end. The two radiating elements are left as single straight elements. These three formed elements are supported by two cut and shaped blocks of nylon

I have not shown the dimensions of the cut blocks but the inserts in the first picture show you exactly how they are formed. It all depends upon what size wooden mounting boom you have. It could of course be metal, but I had a bit of wood sitting doing nothing on the balcony. The only important bit is that the stub should be 1/4-wave in length, not counting the shorted (folded) end.

Insert the center spacer first then just push-fit everything together (using a little brute force). The vertical / horizontal holes in the end-block must have an electrical connection between the stub and driven elements. I used a bit of ferrous (it will stick to a magnet) wire from a component lead, threaded through the holes so that there was a good contact between the two. Copper is well separated from aluminium in the atomic scales so, given time, you will find corrosion between anode and cathode metals such as copper. In case you did not know it, most of your resistors and capacitors use ferrous wires, just take a magnet and test them. The nylon chopping block is more than adequate to support the elements, even in high winds

Connections are made 15cm (6") from the closed end of the stub. The stub is fed with a 50-200 ohm coaxial unbalanced to balanced balun. Using RG58 or URM76 the length of the loop forming the balun needs to be 0.33 x wavelength. A 1/2 wavelength radiating element for 145 MHz is 1030mm and the length of the coaxial balun should be about 690mm, folded to form a 345mm loop. You could, of course, simply roll it up!

I have recently seen several articles published using this type of antenna made from copper pipe, but I think that my method is far easier to make as well as costing virtually nothing in both money and effort (if the wife does not catch you). VSWR? I never even adjusted mine; it didn't need it!

Super J-Pole Antenna

0 comments at 7:53 AM

The antenna system about to be described here is a superset of the classic "J-Pole" design. The basic J-Pole has a gain comparable to a dipole - about 2.5DBi. The author wanted something better, so he investigated several types of antennas. An omnidirectional pattern was desired. Also, minimal skyward radiation and minimal radiation back to the building on which the antenna is installed was a requirement. A vertical design addressed these concerns. The radiation pattern of this antenna approximates that of a doughnut lying on its side. Maximal coverage of populated areas is achieved in this way. The gain of the antenna described herein is about 8.8DBi. Switching to this antenna has much the same effect as tripling or quadrupling transmitter power

The 4-bay J-Pole antenna, nearing completion, just after the wooden mast received a coat of black epoxy paint. Note circular phasing stubs, which are non-radiating 1/2-wave transmission lines. The entire radiating element set is formed of one continuous piece of 10 AWG aluminum wire, measured and bent at the precise 1/2-wave intervals. Light weight was a major engineering requirement for this project, so laminated wooden strips and aluminum wire were chosen as the main materials. This antenna's support is tapered thinner at the top end. The design was successful, since the bottom of the antenna may be easily lifted and the antenna held out horizontally in front of the person, without bending or snapping in half. Such a strength to weight ratio makes it possible for a single man to raise this 30 foot antenna, nailed to the end of a 12 foot 2x3 without assistance. The entire antenna, by itself, weighs just about 8 pounds. Earlier designs became too heavy after more than 2 bays were included.

Detail of the matching transformer assembly and phasing stub assembly. The matching system is of the classic "J" variety, functioning much like an autotransformer voltage step-up at R.F. frequencies. The phasing stub at right is a half-wave delay line -- essentially, a half-wave antenna, folded back on itself so it does not radiate. (See "Phasing Stub Operating Principles" later in this document.) The spacers for the phasing stubs are 1-1/4" cut pieces of computer card cage guides. Snap-in holes to snugly wrap around the 10 AWG aluminum wire were formed in the plastic by melting through with the tip of a hot soldering iron.

Detail of a choke balun, or current balun. Unbalanced antenna currents naturally flow back on the outside of coax feeder lines; this choke presents a high resistance to those currents, effectively blocking antenna currents from carrying back down the outside of the feeder and causing various potential problems with SWR, loss of power at the antenna, etc. Two of these baluns are placed 1/2 wave apart for very effective suppression. Note the wooden slider assembly made from furniture-grade Ash wood and a hardwood dowel. The photo at right shows the sandwiched PC boards that form the sliding contacts which connect the feeder line.